Apartment Needed for 3 Months

I am trying to help find a more suitable accommodation for a friend of mine who arrived last Sunday in Philadelphia from Poland to do a three-month's sub-specialty fellowship at HUP. She would be interested in renting a furnished 2 bedroom (or 1 bedroom if a sleeping area also in the living room) apartment for three months, where she, her husband and son (both of whom will be coming only for several weeks) could stay. She is currently in an old apartment in a poor condition on South Street (close to Front St.), for which she pays $900/month. Anyone knowing of options can email me, Lucy.